Method and apparatus for shaping bimetallic blanks



g- 19, 1952 s. K. WELLMAN ETAL 2,607,245

METHOD AND APPARATUS FOR SHAPING BIMETALLIC BLANKS Filed March 25, 19456 Sheets-Sheet 1 Fla.

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Aug. 19, 1952 s. K. WELLMAN ET AL. 2,607,245

METHOD AND APPARATUS FOR SHAPING BIMETALLIC BLANKS 6 Sheets-Sheet 2Filed March 25, 1945 vllrlllllllll NK r 2% M Mao/um Z W @K M waw w wv aM m Aug. 19, 1952 S. K. WELLMAN ET AL Filed March 23, 1945 6Sheets-Sheet'S Awe-mes.-

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Aug. 19, 1952 METHOD AND APPARATUS FOR SHAPING BIMETALLIC BLANKS FiledMarch 23, 1945 S. K. WELLMAN ETAL 6 Sheets-Sheet 4 g- 1952 s. K. WELLMANETAL 2,607,245

METHOD AND APPARATUS OR SHAPING BIMETALLIC BLANKS Filed March 23, 1945 v6 Sheets-Sheet 5 A r WR/VEK S. K. WELLMAN ET AL Aug. 19, 1952 2,607,245

METHOD AND APPARATUS FOR SHAPING BIMETALLIC BLANKS 6 Sheets-Sheet 6Filed March 23, 1945 WVE/VTORSI 54mm: lf; IiuMA/v Fume/ad [on Er W a. M

ATTQRNEY.

Patented Aug. 19, 1952 UNITED STATES PATENT OFFICE.-

METHOD AND APPARATUS FOR SHAPIN BIMETALLIC BLANKS' Samuel K. Wellman,Cleveland Heights, and- Francis J. Lowey, Bay Village, Ohio, assignorsto The S. K. Wellman Company, Cleveland,

Ohio, a corporation of Ohio. 7 Application March 23, 1945, SerialNo.584,434

9 Claims.

This invention relates method and apparatus forthe controlled bending toconical shape of bimetallic articles having layers of differentplasticity.

Bimetallic articles. having layers of different plasticity are in quitecommon use as machine elements. Articles ofthis type may be a solidmetal backing -member to which is integrally bonded a sintered facing ofa mixture of metallic and non-metallic powders. Such articles have foundincreasing use as friction and anti-friction machine elements for use asbearings and for 'use as brake and clutch friction members. The facingmaterial possesses characteristics not obtainable with solid metalarticles and. as a result has found many unique applications. Forcertain uses of such articles it is necessary to bend or form them tocurved configuration, as where the article is to form an annular bearingor a curved brake shoe facing. This is often difficult due to'the lowtensile strength of thesintered metal facing and its tendency to crackand chip when placed in tension. This is particularly' truewhen'attemptsare made to bend a. fiat bimetallic article to curvedconfiguration with the sintered facing disposed on the outer or convexface 'of the solid metal backing member. Numerous attempts have beenmade to devise satisfactory apparatus and methods for doing this. One,satisfactory solution is set forth in Wellman Patent No. 2,289,311,issued July '7, 19.42. the progressive, mechanical working of successivelateral areas of the sintered metal facing of anelongated bimetallicblank to on the facing and cause. the bimetallic article to bend, is setforth in the pending applications of F. J. Lower et. a1... S- N. 89.132,le May 9. now Batent No. 2.40%.808. ranted Ju y i and of. Wellman. N.555.11 le S ber 21.1944.

-The present inventicn is concerned with the utilization; in a(inferential manner of the prina sl of pro ressive mecha i a in t f abimetallic article in a controlled manner to a predetermined conicalshape.

It is an object of our invention to provide a novel apparatus for the.controlled bending of bimetallic articles having layers of differentplasticity to a predetermined conical shape characterized by theemployment of pressure rolls, at least one of which has a'comcal shape.

It is a further object of our inventionto provide an improved apparatusfor the controlled bending of bimetallic articles to a conical shapewithout scuffing or tearing the surface and which A new and improvedmethod based on gives. uniform results regardless of physical variationsin the articles.

Itv is a still furtherobject of our invention to provide a newand impred method i h, b metallic articles may be amuifately and rapidly bent orotherwise formed to a desired conical shape.

Other and further objects and advantages of our in ention, wi l be a p rn from. he f llo ing description and the accompanying drawings, inwhich: Y

Fig. l is a front elevation of our improved aprarat s for sharin bimetali r icl Fig. 2 is an elevation of the right end of the appa a us o Fi1;

Fig. 3 is a vertical section on line 3--3 of F si;

Fig. 4 is an end elevation of the upper portion of tne'apparatus of Fig.l, but on an enlarged scale; I

Fig. 5 is an enlarged front view of the lower portion of the roll standof Fig. 1, parts being in s ction; I

I Fig. 6 is a horizontal section on line 6-40 of s. I

Fig. 7 is a vertical section on line I-T'I of Fig.

5 with the .rollstarting device in neutral posiion Fig. 8 is a ViWsimilar to Fig. 7, but with the 7 roll starting device in elevatedorfeeding position;

- Fig. 9 is a diagrammatical showing on a greatly enlarged scale of asection of a bimetallic articlein position between the rolls. of theapparatus, the section being taken in a direction parallel to the axesof the rolls;

Fig. 10 is a plan view of a fiat arcuate bimetallic blanle suitable forbending to conical shape; I

Fig. 11 is a side elevation of the blank of Fig. 10;

Fig. 12 is a vertical section of the blank on line l2.-.-+l2 ofFig. 11;a

' Fig. 13 is a side elevation of the blank of Fig. 10 afterit has beenbent according to the teachings of our invention;

. Fig. 14 is a vertical section on line I l-.44 of Fig. 13; and

. Fig. 15 is a diagrammatical vertical section through the rolls of theapparatus and showing the work in process of being bent, the sectionbeing taken in a direction at right angles to the axes of the rolls.

Referring now to Figs. 1 and 2, the main elements of the apparatus willbe generally identified before describing them in detail. It will beseen that the apparatus comprises a base I on which is mounted a rollbending unit generally indicated at 2, and a motor drive generallyindicated at 3. The roll bending unit 2 comprises a frame generallyindicated at 4 in which is rotatably mounted the idler roll 6 and thedrive roll 1. Both rolls have conical rolling surfaces and have theiraxes located in the same plane.

It will be observed that the small ends of the.

rolling surfaces are adjacent each other and that the roll axes areinclined to each other. For convenience, roll 6 is designated as aconical roll and roll 1 as a drive roll. The drive roll I is connectedthrough the telescoping shaft I2 and universal joints [3 and I4 to thedriving shaft 42 and comprises an upstanding cylindrical wall 49 weldedto the upper side of the plate 42 at 5| and a circular top plate 52welded at its circumference 53 to the upper edge of th cylindrical wall49. The cylindrical wall 49, the top plate 52, and the backing plate 42cooperate to define a 8 of a reduction gearing unit 9 integral with Ithe electric motor II.

The drive roll 1 is mounted in the frame 4 in bearings which ar capableof vertical movement. Pressure applying units generally indicated at I5and I6 are mounted on the upper end of the frame 4 and are operativelyconnected with the bearings of the roll I, all as will be described ingreater detail hereafter. The conical roll 6 is freely rotatable infixed bearings carried in the frame 4.

The work to be bent by the machine is fed between the two rolls 6 and l,the rotation of the drive roll by the motor ll serving to feed the blankbetween the rolls and to'rotate the lower conical roll 67., A startingdevice generallydesignated as l! is provided for the conical roll 6 toaid in starting the work between the rolls.

Suitable mechanical controls are provided for the operators of theapparatus. Thus, the pressure applying units 15 and I6 are provided withsuitable control valves to adjust the pressure applied to the drive rollI. The electric motor ll carries a master switch l8 which selectivelyconnects the foot switches I9 and 2| with the source of electricalenergy.

Now that the major components have been identified, the apparatus willbe specifically described. Referring to Figs. 3 and 4, it'will be seenthat the frame 4 of the roll bending unit comprises a base plate 22adapted to be bolted at 23 to the base I, shown in Fig. 1, which restson a suitable foundation, such as a concrete floor. Extending upwardlyfrom the base 22 and welded thereto are the spaced side plates 24 and26. As

seen in Fig. 4, the upper portion of the plate 26 is bifurcated and hasthe upstanding parallel portions 21 and 28 which cooperate to define avertical slideway or guide for reception of the bearing block 29 of theroll 1. p

The foot switches I9 and 2| are secured to the lower portion of the baseI, see Fig. 2, and each switch has a pivoted foot pedal 20, 25 which isspring pulled upwardly.

The pressure applying unit I6 is positioned above the side plate 26 andis held in spaced relation thereto vby means of a bolt 3|, see Fig. 4,which 'is threaded into the upper end of the portion 21 and a bolt 32threaded into the upper end of the portion 28. These bolts extendthrough openings 33, 34 in a channel member 36 of the pressure unit I6.Long sleeves 31, 38 surround the bolts and serve to space the channelmember 36 above the portions 21, 28, and nuts 39, 4| on the upper endsof the bolts 3|, 23 serve to secure the channel member 36 in position.

The channel member 36 serves as a supporting frame to carry the backingplat 42 of the pressure applying unit, see Fig. 3. This backing plate 42is bolted at 43 to the ends of the channel memchamber 54.

An opening 56 through the center of the backing plate 42 providescommunication between the chamber 54 and the diaphragm 46. It is thusseen that if gas under pressure is admitted to the chamber 54, thediaphragm 46. will also be under pressure and will be expandeddownwardlygto a slight extent.

A downwardly extending shield 51 is secured to the margin of the backingplate 42 to 'serve'as a guard in case of rupture of the diaphragm 46.

The chamber 54 is connected to a source 58,:of gas, such as air,'underpressure by means of the pipe 59 andpressure regulating valve 6|. Thepressure regulating valve 6| is provided with anadjus'ting handle 62, apressure gauge 63 to indicate the line pressure of the gas from thesource and a pressure gauge 64 to indicate the reduced pressure'cf theair in the chamber 54. This pressure regulating valve BI is of the usualconstruction for maintaining a constant reduced pressure in a chambersuch as that at 54 regardless-of variations in the pressure from thesource 53. The valve permits adjustment of the pressure in chamber 54 byturning handle 62. A pressure relief valve 66 having an adjustmentnut'6l and an exhaust'opening 66 connects at 69 with the chamber 54 toprotect the diaphragm 46 in case of failure of the pressure regulator 6|or improper adjustment thereof by an inexperienced operator.

A circular pressure plate H is disposed immediately below the diaphragm46 and has a downwardly extending shaft 12 slidably received in abushing 13 which is threaded into an opening 14 in the channel member 36and into a threaded nut 15 welded to channel member 36 in line with theopening 14. The lower end of the shaft '12 has a right hand thread I6which is received by the long adjusting nut 11. The lower end of theadjusting nut 11 has a left hand thread 18 for threadably receiving thedownwardly extending bolt 19 which has a square head 8| received in anopening 82 in th'e'upper end of the bearing block 29- 'and securedthereto by means of' a pin 83. It will be seen that the admission of airor other gas under pressure to the chamber 54 will cause the diaphragm46 to bulge downwardly and apply pressure to the pressure plate H whichwill communicate this pressure through the rod12 to the bearing block 29which rotatably mounts one end of the drive roll 1.

The long nut 11 may beturned to adjust the vertical position of the roll1 and pressure plate H to accommodate dilferent thicknesses of work.

A bolt 84 has its head disposed under the center of the bearing block 29and is threaded intothe side plate 26. The head of the bolt serves as astop to limit downward movement of the bearing block 29. The threadedbushing 13 serves as an adjustable stop to prevent excessive downwardmovement of the diaphragm 46.

I The drive roll 'I' is of tapered or conical shape in its central orrollingportion as isevident-from Fig. 3. This shape is selected so thatthere is no relative sliding movement'between'the surface of the rolland the surface of a flat arcuate'blank (Figs. and 11) fed between thetwo rolls. The tapered or conical shape eliminates surface scuffing andinsures true rolling contact.

The bearing block- 29 of the drive roll 'I is provided with a centralopening 86' for reception of the ball bearing 8-I. The outer race 96" ofthe ball bearings 81 is held against a shoulder 91 of the bearing block29' by means of the retainer plate 88* and bolts 89'. The inner race 9|of the ball bearing 81 is held against theshoulder' 92 of the drive rollI by means of the retainer plate 93 which is bolted at 94 to the end ofthe drive roll ,I. The outer race- 96 of the bearing 01 has an arcuatecross section to permit a limited amount of tilting movement of thedrive roll I and a small variation in the angle of inclination of theaxis of the drive roll I with respect to the axis of the conical roll 6.A packing ring 90 encircles the roll 1 adjacent the bearing 81 to keepoil from the driving surface of the roll.

The pressure applying unit I5 and the frame side plate 24' of the lefthand side of the roll bending unit of Fig. 3 are constructed in asimilar manner to those of the right side which has been described indetail. An inspection of the drawings shows that this left side has apressure chamber 98, a pressure regulating valve 99,

and a diaphragm IOI for applying pressureto the pressure plate I02 whichin turn applies pressure to the bearing block I03 of the left side ofthe drive roll I, through the shaft I04, adjusting nut I00 and bolt I05.A stop bolt H0 is also provided under the bearing block 30. The pressureunit I5, as shown in Fig. 3, is disposed above the pressure unit I6 thusrequiring a longer shaft I04, but otherwise the construction is the sameand will not be further described.

The conical roll 6 is rotatably carried on a stationary axle I06 whichhas an enlarged head I0! received in an inclined opening I08 in the sideplate 24. A pin I09 extends through the side plate 24 and the head I0'Ito hold the axle against movement. A thrust bearing III is disposedbetween the head I01 and the end of the conical roll 6, while sleevebearings H2 are disposed between the roll 6 and the shaft I06. As shownin Fig. 3, the axle I06 is disposed at an angle to roll I and the upperend thereof is received in an inclined opening II3 in the side plate 26.

The conical roll 6 is generally of truncated cone shape and is providedwith a channel I I4 defined by the shoulders I I6, I H for reception ofthe work.

The conical roll 6 is provided with a starting device generallyindicated. at I'Ifor imparting an initial rotation to the conical roll,see Figs. 2 and 4. This starting device operates on the pawl and ratchetor over-running clutch principle and is provided with handles I2I andI22, extending outwardly from the machine. An operator standing in frontof the machine and raising the handle I2I to a limited extent willrotate the conical roll 6 so that the top moves away from the operator.

Similarly, an operator standing on the other side of the machine canrotate the conical roll in the opposite direction by raising the handleI22. This raising of the handles'and partial rotation of the conicalroll 6 is necessary to initially feed a bimetallic blank between thepressure or drive roll I and. theiconical'riolf 6-: :Once the blank hasbeen started between the twosrolls thecontinued rotationof thedriveirollI by 'the motor drive unit 3- will serve. feedz. the-blank between therolls and rotame ftheilowenconical roll 6. I 2i I The starting device Iis best illustrated in Figs. 5" through 8. It comprises: a flanged-feedcollar I23 rotatably encircling tHe st'atiOnary' axle I06 of the conicalroll and-secure'dto. the conical roll 6 by means of the threespacedlpins I24, see Fig. 5. The" feed collar 1:23 has a raisedperipheral flange or rim. I 25' which is adapted to be engaged bythepawls' I 21'and I528- of the starting device to rotate-theconicalroll; I n

Spaced-handle carrying plates I29 and I3'l have circular openings I32 atthe center thereof for reception of the collar I23, the-flange il25'ofthe,

collar I23 being locatedbetween the: plates I29 and I3I- as showninFigs.3 and 5.

The handles I2I and l22 extend' outwardly from the plate I29 and aresecured thereto by means of bolts I33 and I34. It willthus be seenthat-the raising of the handle" I'2I will cause the plates I29 and I3'Ito rotate on} the collar I23. The plates I29 and I3I- are 'heldinspacedrelation by means of the lower spacing member l'w and the upperspacingmember 131,-seeFig. 5. The plates and the lower spacing memberI36 are welded together while thei'upper' spacing member I31 is securedto th'e plates In and-I31 bymeansofthepinsl30." The pawl I2I is disposedbetweenthe plates I29 and I3I and is pivoted 'th'ereto -at I35, 'seeFigs. 7 and 8. Similarly thepawlf I28 is disposed between the plates onthe other side of the axle I06 and pivoted'bymeans' of the pin I38. Thepivot pins I35 and I36 are held in place by means of cap screws I45 andwashers Each pawl is provided at its inner or free endwith a cot-- terpin I39 extending through a-hole in the pawl and having its headdisposedon the lower side of the pawl. A spring I 4I' 'conne'cts each cotter pinwith a pin I42 extending through the loop of the spring'and spanning theplates I29 and I3I. The springs serve to resiliently pull thepawlsdownwardly.- A vertical plate I43,, see Figs; 5,7- and 8, issecured by the bolts I44 to the side plate 26 of the main frame of theroll bender unit and is provided with upwardly extending spaced fingersI46 and M1 which extend upwardly between the plates I29 and I3I onopposite sides of the collar I23. The upper ends. of these, fingersserve as stops to prevent downward rotation of the pawls I21 and I28when the starting device is in the position shown in Fig.. '1 andhaveinclined cam surfaces. I59, I60. for. a purpose later described. 1 J Inthe neutral positionshown in Fig. 7, the length of the pawls I21 and, I28.i such that their inner ends are .not i .contact with the flange I25of the collar'I23 and the conical roll 6 is free to rotate. The startingdevice is held in this neutral position by means of spring plungers I48and I49. *The plunger-I418 is slidably received in the'cylinder I5I-which is welded to the upper edgesof the plates I29 and I3I. A springI52 is disposed in thecylinder I51 to urge the plunger I48 out of thecylinder. The exposed end I53 of the plunger I48 engages a fixed stopI54 carried. by a plate I56which has an opening I51 for reception of theaxle I06; see Fig. 8. A set screw I58 serves tosecure the member I56 tothe axle I96 and thus: hold the'stop I54 against rotation.-- :1 Theplunger I49. is lconstructed in the same manner as the plunger :I48andit will be evident that these two 'plungers serve to'maintain thestarting device I I normally in its central position as shown in Fig! 7..If the starting device is operated by lifting-one, handle to theposition shown .in:Fig. 8-;the spring I52 will be compressed and thestarting-devic will be pushed back to neutral position on release of thehandle. 7

The rotation of the starting device "by lifting the handle I2I from theposition shown in Fig; 7 raises the pawl I21 ,from the stop finger I46and permits it to rotate in a clockwise direction and engage the feedcollar I23. Continued elevation of the handleto, the position shown inFig, 8 will rotate the feed collar [23 and the conical roll 6. Duringthis rotation the opposite pawl I28 rides over the inclined cam'surfaceI59 of the stop finger I41 and is kept'out of engagement with the flangeI25-of the feed collar I 23. On release of the handle I2I the spring I52will return the starting device to its initial position, the pawl I21freely riding over the flange I 25 during this returnmovement. Duringthis return the inclined cam surface I59 serves to keep the pawl I28 outof engagement with the feed collar I23.

The upper spacing member I31 which serves to space apart the plates I29and I3I is provided with an upwardly extending stop I6I normallydisposed between the ends of the plungers I48 and I49. Rotation of thestarting device I1 and the stop to the position shown in Figure 8 causesthis stop member I6I to hold the plunger I49 in inactive position andout of contact With the fixed stop I54. It will be observed that thesetwo stops I 6|, I54 cooperate in the normal position of Fig-7 to formone stop. 4 I

The starting device may be operated to impart an initial rotation to theconical roll Bin a reverse direction to that described above by liftinghandle I22 whereupon pawl. I28 will engage the flange I25 of the feedcollar I23 to rotate the conical roll 6 and pawl I 21 will be-renderedinactive by the cam surface I60.

It will thus be seen that the starting member I1 is in essence areversible over-running clutch which will enable an operator to impartan initial rotation in either direction to the conical roll 6 whilepermitting faster rotation of the conical roll after the work has beeninserted between the two rolls.

It will be noted that the pawl stop member I43 having the upstandingfingers I46 and I4! which serve as stops for the pawlshas elongatedholes I62 for reception of the bolts I44, see Fig. 8. This permitsvertical adjustment of the member I43 to vary the normal position of thepawls to insure clearance of the pawls from the flange I25 when thestarting device is in normal'position.

While we have described the starting device as applicable here to theconical roll 6 and the roll I as being power driven, it is apparent thatthis relation may be reversed if desired. Also the starting deviceillustrated is useful with other rolls such as cylindrical rolls and itis obvious that there are other modifications of starting devices whichmay be used to impart an initial rotation to the conical roll 6. J

As indicated above the conical roll 6 is provided with a channel II4defined by the shoulders I I 6 and I IT. The construction of thischannel is of considerableimportance and is shown in Fig. 9 on anenlarged scale. The channel II 4 has a flat bottom I63. The shoulder II6has a minor side wall portion I64 extending upwardly at right angles tothe bottom I63 and then a major inclined side wall portion I66 which isdisposed at a slight angle to the right angle wall portion I64. Theshoulder I I1 is similarly constructed with an upstanding right angleside wall portionJIB'I and an inclined side wallportion I68.

Fig. 9- also shows a bimetallic blank I'Illin position between theconical roll 6 and the drive roll I. It will be observed that the steelbacking member "I of the blank snugly fits in the portion of the channeldefined by the bottom I63 and the right angle side wall portions I64 andI67. The sintered powdered metal portion I69 of the bimetallic blanknormally has straight sides but the roll bending operation hascompressed the porous sintered material and caused the sides to bulgeoutwardly as shown in this figure. The inclination of the side wallportions I66 and I68 is to provide a space into which the sintered metalcan expand. Unless this relief space is provided the sintered facingwill be badly chipped and cracked at the sides by the rolling operation.7

The inclined side Wall portions I66 and I68 serve another function inkeeping the blank in the channel. If the blank attempts to rise upwardlyand ride out of the channel the inclined walls will guide it back intoposition. The angle of inclination of the inclinedportions I66 and I68appears to be rather critical. If the angle is too great the blank willbe apt to ride out of the channel. If the angle is too small there willbe insufiicient space for the bulging of the sides of the sinteredmaterial. Furthermore, if the angle is too small, the blank will not beguided into place and if it becomes misaligned, it will remain out ofline and the steel backing will be curled or bent and the facingcracked. We have found that the angle of inclination between the majorside wall portion and the plane of the minor side wall portion should befrom 4 to 15". For a conical roll having a channel vII l about 3% wideand diameters of 10" and 11 A at the sides of the channel, an angle ofinclination of about 7 between the inclined wall portions I66, I68 andthe planes of the right angle wall portions I64 and I 61 of the channelII 4 appears to function best.

A channel of the configuration shown in Fig, 9 may also be used withcylindrical rolls and jigs to form bimetallic blanks to cylindricalshape and is very useful in preventing twisting and misalignment of theblank during the rolling operation. The importance of preventingmisalignment of the blank during the rolling operation is readilyapparent. In the case of a conical roll such as shown in Fig. 5, theshape'of the final blank depends on its lateral position on the conicalroll during the rolling operation. If the conical roll 6 had no channelit would be difficult to insure that the blank passed between the rollsat thatparticular circumference of the conical roll which would insurethat it be bent to the desired configuration. Furthermore, if the blankenters the rolls at an angle to the axes it will be bent or twisted toan irregular shape. These problems are also present with cylindricalrolls and jigs for if the blank enters at an angle, it will be formed toa distorted shape resembling a portion of a corkscrew. Thus a channel isof great value in insurin that the article to be bent will achieve thedesired final shape. 'The cross-sectional shape of the channel isimportant in insuring that itachieve these functions.

It is of course "apparent that the right angle side wall portions l64and l6! of thechannel I M are necessary to retain the blank in place andprevent riding out of the channel. If the inclined portions I66 and I68extended to the bottom I63 of the channel, it would-be morediflicult tomaintain the blank in position. I

The theory and method of operation on the roll bending apparatus canbest be understood by references .to Figs. .11- to 15. A blank I10suitable forforming to curved shape is illustrated in Figs. 10 to 12 andis shown ascomprising a sintered powdered metal facing I 69 integrallybonded to a solid. metal backing :member .1111. As shown. in Fig. 10this blank :is of ;genera1ly,flat, arcuate formation. After beingprocessed intaccordance with our invention this blank .will assumetheshape shown .in Figs. .13 and 14 as a generally conical memberlhavingthe .sintered facing I69 disposed on the exteriorior convex .s'ide ofthesolid metal backing member.

- The-blank of Fig, 10 may be :produced inany manner, but we prefer toproduce itasfollows;

The powdered metal facing is produced by.intimately mixing-metallic andnon-metallic powders to form a predominately. metallic mixture ofdesired composition. If the-articleisto be used for clutch or brakepurposes-we have found that the following mixture is suitable l lfzthearticlepisto be used as :ananti-friction material, as ,for abearing,v the following compoe sitionissnitablez.

metal backing' member; which for example may be of steel for strength orof copperfor' heat, conductivity. The assembled unit 'of facing andbacking are pressed'together-under a pressureof from 100 to 250 poundsper square inch while being heated to a sufiicient temperature and-for asufficient length of'tim'e under non-oxidizing conditions to sinter' thepowdered facing-and bond it to the backing member; 1

'In the'case'of -composition-A,-a temperature of 1425 to ll-O -F.'-isadequate to-sinter the mixture andbond itto asteel back-ingmember. Formixture B, a lower-temperature of --around 1300 F. should be used. I Y ITheblank' may be made-to the exact shape shown inFig. l0 byusing moldsand dies of proper shapeor it may becut to shapefrom-a larger blank. a i1 ln order to achieve a strong-union between the to sintered facing andthe solid metal backing member, the surface of the backing member mustbe properly prepared before the heatin operation.

Numerous methods for accomplishing this are set forth in Wellman PatentNo. 2,178,527; issued Octoberfil, 1939, but we prefer to use the methodinvolving the chemical cleaning of the surface followed by theapplication thereto of a very thin c r plat ng ore sui abl etal u ascopp or nickel. This plating is exceedingly thin, havillg a thickness ofaboutQQOOZ inch,and disappears during the heating step. It functions asa protective medium to prevent oxidizing of the backing member duringtheheating stepvby the moisture and air absorbed or adsorbed by thepowders.

.As has been set forth the co-pen i g pp cationspreferred to above,bimetallic articles of this type may be satisfactorily formed to aconical shape by progressively mechanically working in a difierentialmanner the more plastic layer which in this caseis thesintered metal.aci This is achieved bygraduating across the width of the blank thedegrees of progressive mechanical working. For example, cylindrical 70.15 can be used to form theaflat, arcuate blank of Fig. 10 to conicalshape by adjusting the rolls vso that their axes and their surfaces aredispose at a slight angle in order to workoneedge of the facing moreseverely than the other. This greater severity ofworking resultsingreater elongation of that portion of the facing and a consequentdegree of bending. The cylindrical rolls may be rigidly held inapredetermined tapered spacing,

The co -pending applications set forth a variation on this process inwhich the differential working is achieved by varying the pressureapplied by the rolls across the face .of the blank.

. The use of cylindrical rolls i s-objectionable however, in that itrenders it diflicult to readily produce conical-articles even though abending jig or form is utilized. The apparatus of the present inventionis designed to differentially work in a progressive manner successivelateral'areas of such -facings and to utilize a conical roll which alsofunctions as a jig.

In the apparatus shown, the differential working is preferablyaccomplished by applyin greater resilient pressure to one side of thedrive roll 1 than to the other side. Thus the pressure applying unitHiis adjusted sothat it. will apply a greater pressure to the bearingblock .29 of the driverolll thanis applied by the pressure unit .15 tothe other bearing block Hi3. As a result of this, the degree ofmechanical working of the blank will begraduated across the blank.

.Thus it will be observedby reference toFig. 9 that the overallthickness of the facing I59 and backing ill of the bimetallic blank llilis less at the rightside of the figure than .at the left side. Similarlythe space between the surface of, the drive roll 1 and the bottom I63 ofthe channel I [.4 gradually "decreases from the left to the right inthat figure. This is a result .of .thegreater 'pressure'on the righthand side of the roll and the more severe workingzandelongation of thatportion of; the blank. This. greater workin and elongation will cause agreater bending of that portion of the blank resulting in. the bendingof the blank to the conical shapeshown in FigslS and 14..

Fig. 9 .showsthis: diiierential working on a greatly exaggerated scale;In practice this variation will amount to only, a fewthousandthso'f .an

inch, as will be evident from the example given below.

This feature and the general operation of the apparatus is evident fromFig. 15 which diagrammatically illustrates the method of operating theapparatus. This figure shows in section the upper drive roll I and thelower conical roll 6 withia bimetallic blank I10 disposed in positiontherebetween. The rolls are rotated in the direction of vthe arrowsshown and the blank passes between them from the left to the right ofthat figure. Theblank is shown in its dotted line position midwayduringits first passage between the rolls and it W111 be observed thatthe right hand portion of the blank has been partially bent. On thesecond and succeeding passage between the rolls,the blank is shown insolid lines in its midway positionand as having been bent on its righthand portion to the contour of the roll. 1 a

It will be seen that the working of the sintered facing'of the blank andthe consequent differential elongation of the same has caused the blankto be differentially bent until it attains the conical contour of thechannel of the conical roll 6. The conical roll 6 therefore serves as atemplate or jig to accurately predetermine the finished shape of theblank.

As set forth above, the difierential bending of the blank to conicalshaping is preferably accomplished by'applying a different amount of.pressure to the pressure applying unit I than to the pressure'applyingunit. It. These pressures are produced by gas under pressure acting ondiaphragm-s and is a yieldable pressure due to the compressibility ofthe pressure medium.

As stated above, the pressures applied to the blank must be suitablychosen to achieve the desired bending. If the pressures are too greatthe sintered facing will be expanded to too great a degree and. the.blank will be over'bent. If the pressures are too low, .too many passesbetween the rolls will be required for proper'bending. Similarly, thevariation in pressure between the chamber 98 and the chamber 54 mustbeinaintained to achieve the required differential bending. With theapparatus illustrated these features are not too critical andsatisfactory bending is readily achieved.

The use of gas pressure to force the drive roll toward the conical rollis highly advantageous in that it greatly reduces variations in resultsdue to variations in thickness and plasticity of the layers of theblank. Since the degree of bending depends on the extent of themechanical working of the more plastic layer of the blank, it isessential that the amount of mechanical working be uniform lengthwise ofthe blank. If the pressure rolls are rigidly held in spaced relation itis apparent that variations in thickness and plasticity of the layers ofthe blank will result in variations in the amount of mechanical workingand the degree of bending obtained. The use of gas pressure as disclosedhere serves to greatly reduce variations in bending due to variations inthe blank. With gas pressure, succeeding lateral areas of the blankreceive the same amount of pressure from the rolls and are workedsubstantially to the same extent regardless of thickness.

If gas or some other compressible fluid is utilized to supply thepressure to the rolls there will be obtained a resilient pressure on therolls. The chambers or accumulator tanks 54 and 98 are provided to.increase the volume of. gas which is applied to the diaphragms .41 andI0 I. The

large volumes of these cham'bers-are necessary in order to maintain thepressure on the diaph'ragms substantially const t,regageless pr slight=upward movements of thediaphrag'ms-due to varia-- tions in thickness ofthe blank'being.b'ent. Obviously springs could be substituted'for thegas pressure diaphragms but we'have found that the disclosed apparatusfunctions very "satisfactorily andis easytocontrol.

The apparatus of the present invention is also adapted to bend a flat,arcuate blank to conical shape without theuse of 'theflyieldablepressure produced by' the pressure applying units I5 and I6. Due to theprovision of adjustment nuts 11 and I00 and the stop bolts 84fand' IID,it is apparent that the drive roll 1' may be adjusted so that it may berigidly held at any predetermined position. If'the stop bolts '84 andIII] are adjusted to elevate the drive roll I to desired position, thenthe roll may be rigidly clamped in this position by turningthe longadjusting nuts '11 and I00 to elevate the pressureplates II and I02 intocontact with the backing plates 42 and IOI. In this condition of themachine it will progressively mechanically work in a differential mannersuccessive lateral areas of a bimetallic blank. However, uniform bendingof a blank and consistency in results require that the blank be ofuniform thickness and plasticity. For these reasons we prefer to use theyieldable pressure provided by the pressure applying units I5 and l6. 7

From the above description of the apparatus and the theory of'operation,the method of operating the machine and of forming the bimetallic blankto the predetermined conical shape should be apparent but will be setforth here for clarity. The machine'is best operated by two persons who40 will stand on opposite sides'of the machine or on the right and lefthand side'as shown in Fig. 2, so thateach operatorhasavailable a'handleI2I, I22 of the starting device I], a foot switch I 9, 2I and access tothe main switch I8 located on the motor. The drive roll I will beadjusted by the operators to proper position by turning the long nuts 1]to raise or lower the roll.. They will also adjust. the stop nut I3 andstopbolts 84 to limit the movement of vthe roll. Then they will admitair to the pressure chambers 54 and 98 by adjusting the pressureregulatingvalves BI and 99 to attain the desired pressure .on thediaphragms 46 andIUI. I a

The operator on one side of the machine will then'step on the pedal ofthe foot switch I9 or H to rotate the drive roll "Tin a directionso'that the top of the roll moves toward him. He will then place a.'flat, "arcuate bimetallic blank in position to feed betweerrthe tworolls. ,The end of the blankwill be pushed between the rolls with thesolid metal backing'member disposed adjacent the conical roll 6 and withthe arcuate side of shorterradius disposed toward the small ends of theconical rolling surfaces of the roll. To facilitate entry of the blankbetween the rolls, he will raise thehandle of; the starting'device toimpart a partial rotation to the-conical roll. Once the blank startsbetween the rolls'it will be rapidly fed forward by'the drive roll 'I,and the starting device will be inactive and the handle may be released.The blank willbefedbetween therolls and will emerge onthe other side. ina partially bent condition as shown inthe clotted line indication inFig. 15. It will be caught by the operator on the other sidev of. themachine who will hand it back to the first operator for second passagebetween the rolls.

The stop bolts -84 and llflfserve to limit'the extent of,downward'movement of the bearing blocks 29 and 30 ofthedrive' roll 1.These stops are necessary toihsure that a bimetallic blank may bereadily fed into the machine. They will be adjusted so that when thebearing blocks 29 and 30 rest upon the stop bolts 84 and llfl'thedistance between the bottom of the channel H4 and the circumference ofthe drive rolll is a few 'thousandths less than the final thickness of"the finished'blank. For example with a blank havin an overall thickness'of .250 inch and which will be reduced during the rolling operation toa thickness of .240 inch, the stop bolts '84an'd 'I II] will be adjustedso that'the spacing between the rolls isapproximately .238. "Thisspacing is sufficient so that anoperator using the starting device I!can force a blank betweenthe rolls and raise the drive "roll 1 upwardlyagainst the pressure exerted by the pressure units 1 5 audit.

In some cases it may be possible to dispense with the starting devicell. For example the entering end of the blank tobe bent'may have a taperproduced thereon as by-grinding to permit starting of the blank. Itis'also obvious thata power drive could be provided for the conical roll6 and that this would eliminate the need for the'starting device 11.However, the apparatu shown has functioned-very satisfactorily withoutresort'to either of these exp'edients.

The configurations of the drive roll land the conical roll '6 are suchthat there is true rolling contact between the'rolling "surfaces of therolls and the surfaces-of the blank. "There is theoretically no slidingmovement between the surfaces of these rolls and'the surface of theblank to be bent.

This elimination of sliding and scufiing of the facing of the blankappears to give a better product. However, the drive roll I could be ofcylindrical shape if such scuffizng is not objectionable.

The thickness of the blank and the relative plasticity of the layerstogether with the diameter of the conical roll 6 determine the requiredpressures for the pressure chambers 54 and 98. In addition the pressurerequired is affected by the number of passes between the rolls which areutilized to bend the blank to final shape.

Although the blank may be bent to final shape in one passage, it ispreferred to use several *passages to eliminate danger of cracking orchipping and overbending.

One specific exampleis as follows. A bimetallic blank having-a-SrA. E.1010 H. R. steel backing thickand a sintered facing of composition Aabove and a thickness of of an inch,

a width of 3%," and an arcuate length of "about 12" is to be bent'toa'conical shape havinga large radius of 5%" and a small radius of 5".For this, the pressure applied 'to chamber 98 the blank from .006 to.010 with one edge being about .002 to .003 thinner than the other. Thisvariation in thickness across the blank is so slight as to benegligible. It of course can be eliminated by starting with a flat blankthat is initially .002 to .003 thicker on the edge which will be giventhe greatest reduction in thickness.

The foot switches 19 and 21 are operated 'by the feet of the operatorsand'are of the reversing type. When the pedal is in elevated position,the switch energizes the motor II to rotate the drive roll I so that thetop thereof moves away from the operator. "When in-lowered position, theroll direction of rotation -"is' revers'ed. The hand switch 18 serves toselectively energize "the switches l9 and "2 l. The'switches act'as-asafety feature to allow the operator to quickly reverse the rollbyraising his foot from the switch pedal.

In actual operation, the operator on one side of the machine will turnthe 'hand switch 1'8 to energize his foot switch and will feed a largenumber'o'f blanks throughthe rolls in succession. These will be caughtand placed in a pile by the other operator. Following this, the secondoperator will assume control over the machine, turn the hand switch 18to energize his foot switch only and will feed the partially formedblanks back through the rolls to the "first operator. Thissequence hasbeen found desirable in that-it reverses the direction of rolling forsuccessive'passes of the same blank, an expedient that apparentlyachieves better results. I

finished bla'nk of Figs. 13 and*l4,1it;is apparent that neither oftheseari'a ti'u'e cones'but are really segments or frusturnsofcdnes. However,the term conical is intended to co'ver t'hese modifications as well astrue-andcomplete-cones.

While the invention has been described with reference "to a'bimetallicblank having-j'a Isintered metalfachi'g', it is applicable to anybimetallic article having layers of different plasticity. The termplasticity is used "to denote those flowable properties of -a' materialwhich permit its being progressively mechanically =workedand elongatedby passage between a pair of opposed pressure rolls. The progressivemechanical working of such a bimetallic article causes'the more plasticlayer to -'be elongated and results in bending of the blank. -In someinstances the sintered faci'ng may be 3 the "least plastic layer, as-wh'ere 'a sint'ered iron facing-is securedtoa backing memberofsoft-sheetcopper. '=Passageof-'such a blank between pressure {roll-swould result in reverse.

bending with the sintered facing disposed on the inner or concave sideof the backing.

Any bimetallic article having layers nf differ- 'ent plasticitymaybeprogressiv'ely mechanically worked according to *our' invention.Thus a blank having solid copper secured to solid steel could be bent'bythe apparatus of'our invention. However, the bending of such solidmetalblanks by using presses or other apparatus presents no greatproblem and our invention finds its greatest use in the "controlledbending to a predetermined shape of bimetallic articles having asintered powdered nietaljfacing; The terms fplastic and plasticity areused to. indicate the *flowable'or deformable properties of the sinteredmaterial which permit the elongation and causethe bending. Whilesintered metallic material is generally of low tensile strength incomparison with'solid metal, such as steel, it does possess the propertyof being plastic or fiowable to a rather high degree. In this respect,it may be said that it is of high ductility in that it is capable ofbeing deformed and hammered out.

The above description and examples are regarded as illustrative only andhave been set forth at length to more clearly describe the invention.vIt is contemplated that there arenumerous-modifications and changeswhich may be made-without departing from the spirit of the invention -and'scope of the appended claims.

1. Apparatus'for the controlled bending of a fiat, arc uate, bimetallicblank to conical shape comprising a supporting frame; a pair of opposedpressurerolls rotatably mounted in said frame with their axes in thesame plane and'inclined to one another, one of said rolls having aconical rolling surface of a contour the same as that desired for thefinished blank; at least one of said rolls being mounted for movementtoward and away'from theother; means for resiliently urging said movablymounted roll toward said other roll under controlled pressure;powerdriven means for rotating one of said rolls; and hand-operatedmeans including an over-running clutch for, imparting an initialrotation to the other roll.,

2. The apparatus of claim 1 in which the overrunning, clutch isreversible operating whereby the roll may be given an initial rotationin either direction.

3. Theapparatus of claim 1 in which the hand operated meansincludesa'feed collar carried by the roll; apivotedplate carryingpivoted pawls, said pawls being disposed on opposite sides of saidcollar and adapted to have their free ends engage said collar; springmeans urging said pawls to rotate into engagement with said collar; andcam means having stops to hold said pawls out of engagement with saidcollar in the normal position of said plate and having cam surfaces toretain one pawl out of engagement with said collar on movementof saidplate in one direction from the normal position and to retain the otherpawl out of contact on movement of the plate in the opposite directionfrom the normal position,

4. In apparatus for the controlled bending to predetermined conical formof fiat arcuate bimetallic ,blanksjof the type having a more plasticfacing layer 1 of sintered metallic material bonded to a lessplasticbacking layer of solid metal, the combination of a pair of rotatablysupported opposing pressure rolls, one of which has a circumferentialchannel defined by a bottom forming the rolling surface of the roll forengagement with the backing layer of the blank and by outwardlyextending side walls with each side wall comprising an inner portiondisposed at right angles to the bottom of the channel and of a radialwidth to engage one edge of the backing layer only of the blank and anouter portion extending outwardly from said inner por tion at adivergent angle to the planethereof so that the top of said channel iswider than its bottom to afford clearance between the side walls of thechannel and the edges of the facing layer of the blank; andindependently adjustable means cooperating respectively with theopposite ends of the two rolls to urge them together with differentpredetermined forces.

. -5. Apparatus asclaimed inclaim 4 in which the angle of inclination,of the outer. side wall portion of the channel to the plane of theinner portion thereof is withinlthe rangeof 4" to 15.

6. Apparatus asfcla'imed in claim '4 in'which the angle of inclinationof the outer side wall portion of the channel to the plane of the innerportion thereof is approximately'fi.

7. Apparatus as claimed in claim 4 in which the rolling surface of thechannel roll is of conical shape. V

8. The method for the controlled bending to a predetermined conicalshape of a flat, arcuate blank of the type having a more plastic facinglayer of sintered metallic material bonded to a less plastic backinglayer of solid metal comprising the steps of providing a pair ofoperavtively supported opposing rolls one of which has a rolling surfaceof-conical shape corresponding to the predetermined finished shape ofthe blank; passing the blanklengthwise between the rolls with thebacking layer in contact with the said conical rolling surface and withthe arcuate blank edge of shorter radius disposed toward the smaller endof said rolling surface; meanwhile forcing the two rolls towardeachother with yieldable pressure that is substantially constant at anypoint lengthwise of the rolls but increases from the larger end to thesmaller end of the said conical rolling surface; and adjusting-theintensity of the yieldable pressure to effect bending of the blank toconformity with the said conical rolling surface.

9. The'method as claimed in claim 8 in which, during passage vof theblank between the rolls, lateral guiding constraint is applied to thelateral edges of the backing layer only of the blank to bring each ofsaid edges of the finished blank into a plane at right angles to theconical axis thereof. I r Y e 4 SAMUEL K. WELLMAN.

FRANCIS J. LOWEY.

REFERENCES CITED The following'referenoes are of record in the fileof'this patent: I 1 3 UNITED STATES PATENTS Number Name Date 7 432,625Kennedy July 22, 1890 908,860 Gustavsen Jan. 5, 1909 1,295,614Scrimgeour l Feb. 25, 1919 1,350,057 Bell Aug. 17, 1920 1,367,015 BrowneFeb. 1, 1921 1,406,895 Reifurth Feb. 14, 1922 1,921,486 Seiferth Aug. 8,1933 2,056,409 Ross Oct. 6,1936 2,152,611 Swartz Mar. 28, 1939 2,190,237Koehring Feb. 13, 1940 2,219,665 Simons Oct. 29, 1940 2,254,674Christman Sept. 2, 1941 Lowey Aug. 10, 194B

